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Tin is a chemical element with the Chemical symbol Sn (from stannum]]) and atomic number 50. Tin is a silvery-coloured metal.
Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent, the so-called "tin cry" can be heard as a result of Crystal twinning in tin crystals; (1985). 9783110075113, Walter de Gruyter. ISBN 9783110075113 this trait is shared by indium, cadmium, zinc, and mercury in the solid state.
Pure tin after solidifying presents a mirror-like appearance similar to most metals. In most tin (such as pewter) the metal solidifies with a dull gray color.
Tin is a post-transition metal in Carbon group of the Periodic table. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, . Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, and has two main , +2 and the slightly more stable +4. Tin is the 49th most abundant element on Earth and has, with 10 stable isotopes, the largest number of stable in the periodic table, thanks to its magic number of protons.
It has two main Allotropy: at room temperature, the stable allotrope is β-tin, a silvery-white, Ductility metal; at low temperatures it is less dense grey α-tin, which has the diamond cubic structure. Metallic tin does not easily Redox in air and water.
The first tin alloy used on a large scale was bronze, made of tin and copper, from as early as 3000 BC. After 600 BC, pure metallic tin was produced. Pewter, which is an alloy of 85–90% tin with the remainder commonly consisting of copper, antimony, bismuth, and sometimes lead and silver, has been used for Tableware since the Bronze Age. In modern times, tin is used in many alloys, most notably tin / lead soft , which are typically 60% or more tin, and in the manufacture of transparent, electrically conducting films of indium tin oxide in Optoelectronics applications. Another large application is corrosion-resistant Tinning of steel. Because of the low toxicity of inorganic tin, tin-plated steel is widely used for food packaging as tin cans. Some organotin compounds can be extremely toxic.
β-tin, the metallic form or white tin, has BCT structure and is stable at and above room temperature and is malleable. α-tin, the nonmetallic form or gray tin, is stable below and is brittle. α-tin has a diamond cubic crystal structure, similar to diamond, silicon or germanium. α-tin has no metallic properties, because its atoms form a covalent structure in which electrons cannot move freely. α-tin is a dull-gray powdery material with no common uses other than specialized semiconductor applications. γ-tin and σ-tin exist at temperatures above and pressures above several GPa.
In cold conditions β-tin tends to transform spontaneously into α-tin, a phenomenon known as "tin pest" or "tin disease". Some unverifiable sources also say that, during Napoleon's Russian campaign of 1812, the temperatures became so cold that the tin buttons on the soldiers' uniforms disintegrated over time, contributing to the defeat of the Grande Armée, a persistent legend.
The α-β transformation temperature is , but impurities (e.g. Al, Zn, etc.) lower it well below . With the addition of antimony or bismuth the transformation might not occur at all, increasing durability.
Commercial grades of tin (99.8% tin content) resist transformation because of the inhibiting effect of small amounts of bismuth, antimony, lead, and silver present as impurities. Alloying elements such as copper, antimony, bismuth, cadmium, and silver increase the hardness of tin. Tin easily forms hard, brittle intermetallic phases that are typically undesirable. It does not mix into a solution with most metals and elements so tin does not have much solid solubility. Tin mixes well with bismuth, gallium, lead, thallium and zinc forming simple Eutectic point systems.
Tin becomes a superconductor below 3.72 kelvin and was one of the first superconductors to be studied. The Meissner effect, one of the characteristic features of superconductors, was first discovered in superconducting tin crystals.
Tin has 31 unstable isotopes, ranging in mass number from 99 to 139. The unstable tin isotopes have a half-life of less than a year except 126Sn which has a half-life of 230,000 years. 100Sn and 132Sn are two of the few with a "Double magic" nucleus which despite being unstable, as they have very uneven neutron–proton ratios, are the endpoints beyond which tin isotopes lighter than 100Sn and heavier than 132Sn are much less stable. Another 30 metastable isomers have been identified for tin isotopes between 111 and 131, the most stable being 121mSn, with a half-life of 43.9 years.
The relative differences in the number of tin's stable isotopes can be explained by how they are formed during stellar nucleosynthesis. 116Sn through 120Sn are formed in the s-process (slow neutron capture) in most which leads to them being the most common tin isotopes, while 122Sn and 124Sn are only formed in the r-process (rapid neutron capture) in supernovae and are less common. Tin isotopes 117Sn through 120Sn are also produced in the r-process. 112Sn, 114Sn, and 115Sn, cannot be made in significant amounts in the s- or r-processes and are among the p-nuclei whose origins are not well understood. Some ideas about for their formation include proton capture and photodisintegration, 115Sn might be partially produced in the s-process both directly and as the daughter of long-lived 115In.
The Latin language name for tin, stannum, originally meant an alloy of silver and lead, and came to mean 'tin' in the fourth century Encyclopædia Britannica, 11th Edition, 1911, s.v. , citing H. Kopp—the earlier Latin word for it was plumbum candidum, or "white lead". Stannum apparently came from an earlier stāgnum (meaning the same substance), the origin of the Romance language and Celtic languages terms for tin , such as French language étain, Spanish language estaño, Italian language stagno, and Irish language stán. The origin of stannum/stāgnum is unknown; it may be pre-Indo-European.American Heritage Dictionary''
The Meyers Konversations-Lexikon suggests instead that stannum came from Cornish language stean, and is evidence that Cornwall in the first centuries AD was the main source of tin.
Cassiterite (), the oxide form of tin, was most likely the original source of tin. Other tin ores are less common such as stannite that require a more involved smelting process. Cassiterite often accumulates in alluvial channels as placer deposits because it is harder, heavier, and more chemically resistant than the accompanying granite. Cassiterite is usually black or dark in color, and these deposits can be easily seen in river banks. Alluvial (placer deposits) deposits may incidentally have been collected and separated by methods similar to gold panning.
Tin(II) chloride (also known as stannous chloride) is the most important commercial tin halide. Illustrating the routes to such compounds, chlorine reacts with tin metal to give SnCl4 whereas the reaction of hydrochloric acid and tin produces and hydrogen gas. Alternatively SnCl4 and Sn combine to stannous chloride by a process called comproportionation:
Tin can form many oxides, sulfides, and other chalcogenide derivatives. The dioxide (cassiterite) forms when tin is heated in the presence of air. is amphoteric, which means that it dissolves in both acidic and basic solutions. Stannates with the structure 2−, like , are also known, though the free stannic acid is unknown.
of tin exist in both the +2 and +4 oxidation states: tin(II) sulfide and tin(IV) sulfide (mosaic gold).
Most organotin compounds are colorless liquids or solids that are stable to air and water. They adopt tetrahedral geometry. Tetraalkyl- and tetraaryltin compounds can be prepared using :
Divalent organotin compounds are uncommon, although more common than related divalent organogermanium and organosilicon compounds. The greater stabilization enjoyed by Sn(II) is attributed to the "inert pair effect". Organotin(II) compounds include both stannylenes (formula: R2Sn, as seen for singlet ) and distannylenes (R4Sn2), which are roughly equivalent to . Both classes exhibit unusual reactions.
Tin is the 49th most abundant element in Earth's crust, representing 2 ppm compared with 75 ppm for zinc, 50 ppm for copper, and 14 ppm for lead.
Tin does not occur as the native element but must be extracted from various ores. Cassiterite () is the only commercially important source of tin, although small quantities of tin are recovered from complex such as stannite, cylindrite, franckeite, canfieldite, and teallite. Minerals with tin are almost always associated with granite rock, usually at a level of 1% tin oxide content.
Because of the higher specific gravity of tin dioxide, about 80% of mined tin is from secondary deposits found downstream from the primary lodes. Tin is often recovered from granules washed downstream in the past and deposited in valleys or the sea. The most economical ways of mining tin are by dredging, Hydraulic mining, or open pits. Most of the world's tin is produced from placer mining deposits, which can contain as little as 0.015% tin. (1992). 9780941375627 ISBN 9780941375627
| +World tin mine reserves (tonnes, 2011) | |
| 1,500,000 | |
| 250,000 | |
| 310,000 | |
| 800,000 | |
| 590,000 | |
| 400,000 | |
| 350,000 | |
| 180,000 | |
| 170,000 | |
| Other | 180,000 |
| Total | 4,800,000 |
| +Economically recoverable tin reserves !Year !Million tonnes | |
| 1965 | 4,265 |
| 1970 | 3,930 |
| 1975 | 9,060 |
| 1980 | 9,100 |
| 1985 | 3,060 |
| 1990 | 7,100 |
| 2000 | 7,100 |
| 2010 | 5,200 |
Scrap tin is an important source of the metal. Recovery of tin through recycling is increasing rapidly. Whereas the United States has neither mined (since 1993) nor smelted (since 1989) tin, it was the largest secondary producer, recycling nearly 14,000 tonnes in 2006.
New deposits are reported in Mongolia, and in 2009, new deposits of tin were discovered in Colombia.
Most of the world's tin is traded on LME, from 8 countries, under 17 brands.
| +Largest tin producing companies (tonnes) | ||
| Yunnan Tin | China | 42.3 |
| PT Timah | Indonesia | |
| Malaysia Smelting Corp | Malaysia | 19.0 |
| Yunnan Chengfeng | China | 23.1 |
| Minsur | Peru | |
| EM Vinto | Bolivia | 6.7 |
| Guangxi China Tin | China | / |
| Thaisarco | Thailand | |
| Metallo-Chimique | Belgium | 20.5 |
| Gejiu Zi Li | China | / |
International Tin Council was established in 1947 to control the price of tin. It collapsed in 1985. In 1984, Association of Tin Producing Countries was created, with Australia, Bolivia, Indonesia, Malaysia, Nigeria, Thailand, and Zaire as members.
During the late 1970s and early 1980s, the U.S. reduced its strategic tin stockpile, partly to take advantage of historically high tin prices. The 1981–82 recession damaged the tin industry. Tin consumption declined dramatically. ITC was able to avoid truly steep declines through accelerated buying for its buffer stockpile; this activity required extensive borrowing. ITC continued to borrow until late 1985 when it reached its credit limit. Immediately, a major "tin crisis" ensued — tin was delisted from trading on the London Metal Exchange for about three years. ITC dissolved soon afterward, and the price of tin, now in a free-market environment, fell to $4 per pound and remained around that level through the 1990s. The price increased again by 2010 with a rebound in consumption following the 2007–2008 economic crisis, accompanying restocking and continued growth in consumption.
London Metal Exchange (LME) is tin's principal trading site. Other tin contract markets are Kuala Lumpur Tin Market (KLTM) and INATIN (INATIN).
Due to factors involved in the 2021 global supply chain crisis, tin prices almost doubled between 2020—21 and have had their largest annual rise in over 30 years. The International Tin Association estimated that global refined tin consumption will grow 7.2 percent in 2021, after losing 1.6 percent in 2020 as the COVID-19 pandemic disrupted global manufacturing industries.
Copper cooking vessels such as saucepans and frying pans are frequently lined with a thin plating of tin, by electroplating or by traditional chemical methods, since use of Copper toxicity can be toxic.
The niobium–tin compound Nb3Sn is commercially used in coils of superconducting magnets for its high critical temperature (18 K) and critical magnetic field (25 T). A superconducting magnet weighing as little as two is capable of producing the magnetic field of a conventional electromagnet weighing tons.
A small percentage of tin is added to for the cladding of nuclear fuel. (2023). 9780871708670 ISBN 9780871708670
Most metal pipes in a pipe organ are of a tin/lead alloy, with 50/50 as the most common composition. The proportion of tin in the pipe defines the pipe's tone, since tin has a desirable tonal resonance. When a tin/lead alloy cools, the lead phase solidifies first, then when the eutectic temperature is reached, the remaining liquid forms the layered tin/lead eutectic structure, which is shiny; contrast with the lead phase produces a mottled or spotted effect. This metal alloy is referred to as spotted metal. Major advantages of using tin for pipes include its appearance, workability, and resistance to corrosion.
Before the modern era, in some areas of the Alps, a goat or sheep's horn would be sharpened and a tin panel would be punched out using the alphabet and numbers from one to nine. This learning tool was known appropriately as "the horn". Modern reproductions are decorated with such motifs as hearts and tulips.
In America, and food safes were in use in the days before refrigeration. These were wooden cupboards of various styles and sizes – either floor standing or hanging cupboards meant to discourage vermin and insects and to keep dust from perishable foodstuffs. These cabinets had tinplate inserts in the doors and sometimes in the sides, punched out by the homeowner, cabinetmaker, or a tinsmith in varying designs to allow for air circulation while excluding flies. Modern reproductions of these articles remain popular in North America.
Window glass is most often made by floating molten glass on molten tin (float glass), resulting in a flat and flawless surface. This is also called the "Pilkington process".
Tin is used as a negative electrode in advanced Li-ion batteries. Its application is somewhat limited by the fact that some tin surfaces catalyze decomposition of carbonate-based electrolytes used in Li-ion batteries.
Tin(II) fluoride is added to some dental care products as stannous fluoride (SnF2). Tin(II) fluoride can be mixed with calcium abrasives while the more common sodium fluoride gradually becomes biologically inactive in the presence of calcium compounds. It has also been shown to be more effective than sodium fluoride in controlling gingivitis.
Tin is used as a target to create laser-induced plasmas that act as the light source for extreme ultraviolet lithography.
Exposure to tin in the workplace can occur by inhalation, skin contact, and eye contact. The US Occupational Safety and Health Administration (OSHA) set the permissible exposure limit for tin exposure in the workplace as 2 mg/m3 over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) determined a recommended exposure limit (REL) of 2 mg/m3 over an 8-hour workday. At levels of 100 mg/m3, tin is IDLH.
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